Paul Logan

Electronic properties of strained Si/Ge core-shell nanowires

We investigated the electronic properties of strained Si/Ge core-shell nanowires along the [110] direction using first principles calculations based on density-functional theory. The diameter of the studied core-shell wire is up to 5 nm. We found the band gap of the core-shell wire is smaller than that of both pure Si and Ge wires with the same diameter. This reduced band gap is ascribed to the intrinsic strain between Ge and Si layers, which partially counters the quantum confinement effect. The external strain is further applied to the nanowires for tuning the band structure and band gap. By applying sufficient tensile strain, we found the band gap of Si-core/Ge-shell nanowire with diameter larger than ∼3 nm experiences a transition from direct to indirect gap.

Strain-modulated electronic properties of Ge nanowires: A first-principles study

We used density-functional theory based first-principles simulations to study the effects of uniaxial strain and quantum confinement on the electronic properties of germanium nanowires along the [110] direction, such as the energy gap and the effective masses of the electron and hole. The diameters of the nanowires being studied are up to

Band structure of Si/Ge core–shell nanowires along the [110] direction modulated by external uniaxial strain

50\text{ }\text{\AA{}}

First Principles Study of Si/Ge Core-Shell Nanowires ---- Structural and Electronic Properties

. As shown in our calculations, the Ge [110] nanowires possess a direct band gap, in contrast to the nature of an indirect band gap in bulk. We discovered that the band gap and the effective masses of charge carries can be modulated by applying uniaxial strain to the nanowires. These strain modulations are size dependent. For a smaller wire

Electronic Properties of Si and Ge Pure and Core-Shell Nanowires from First Principle Study

(\ensuremath{\sim}12\text{ }\text{\AA{}})

First principles study of strained Si/Ge core-shell nanowires along [110] direction

, the band gap is almost a linear function of strain; compressive strain increases the gap while tensile strain reduces the gap. For a larger wire

First Principles Study of Si/Ge Core-Shell nanowires under external uniaxial strain

(20\text{ }\text{\AA{}}\char21{}50\text{ }\text{\AA{}})

Electronic Properties of Strained Si [111] Nanowires

, the variation in the band gap with respect to strain shows nearly parabolic behavior: compressive strain beyond

The Effects of Strain and Quantum Confinement on the Electronic Properties of Germanium Nanowires

\ensuremath{-}1%

Strain and edge passivation induced band gap modulation and effective mass tuning in Armchair Graphene Nanoribbons

also reduces the gap. In addition, our studies showed that strain affects effective masses of the electron and hole very differently. The effective mass of the hole increases with a tensile strain while the effective mass of the electron increases with a compressive strain. Our results suggested both strain and size can be used to tune the band structures of nanowires, which may help in design of future nanoelectronic devices. We also discussed our results by applying the tight-binding model.